What is the chemical process that typically cures alkyds and drying oil coatings?

The curing of alkyds and drying oil coatings primarily occurs through the process of oxidation. In the context of these coatings, oxidation involves the reaction of the unsaturated fatty acids in the resin with oxygen from the air. This allows the coating to harden and form a solid film. As the alkyds and drying oils are exposed to moisture and air, the oxidation reaction leads to cross-linking of the molecular chains, resulting in a durable and stable coating.

While polymerization also refers to a process where smaller molecules (monomers) link together to form larger molecules (polymers), in the case of alkyds and drying oils, it is the oxidation process that is pivotal for curing. Hydrolysis, which involves the reaction of a substance with water, and reduction, which involves gaining electrons or decreasing oxidation states, are not the primary mechanisms by which these types of coatings cure. Therefore, oxidation accurately describes the chemical process responsible for curing alkyds and drying oils, making it the correct choice.